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CN-121990583-A - Titanium silicon molecular sieve, preparation method thereof and application thereof in catalyzing ethylene sulfite oxidation reaction

CN121990583ACN 121990583 ACN121990583 ACN 121990583ACN-121990583-A

Abstract

The invention relates to the field of molecular sieve synthesis, and discloses a titanium-silicon molecular sieve, a preparation method thereof and application thereof in catalyzing ethylene sulfite oxidation reaction. The method comprises the steps of (1) carrying out first mixing on a silicon dioxide source, an alkali source and water to obtain a mixed solution I, wherein the alkali source is a combination of tetrapropylammonium hydroxide and alkyl glycoside, (2) carrying out second mixing on the mixed solution I and water-soluble cellulose to obtain a mixed solution II, (3) carrying out third mixing on the mixed solution II and a titanium source to obtain a mixed solution III, (4) carrying out crystallization on the mixed solution III, and roasting the obtained solid product to obtain the titanium-silicon molecular sieve, wherein the molar ratio of the silicon dioxide source to the alkali source to the water-soluble cellulose to the titanium source to the water is 1:0.1-0.5:0.0001-0.005:0.01-0.2:20-100. The titanium-silicon molecular sieve with high conversion rate of ethylene sulfite and high selectivity of ethylene sulfate can be prepared by adopting the method of the invention.

Inventors

  • CHEN YUKANG
  • CHEN ZHIWEI
  • CHEN MENGCHUN
  • TONG MIN

Assignees

  • 岳阳翰康科技有限公司

Dates

Publication Date
20260508
Application Date
20260129

Claims (10)

  1. 1. A method of preparing a titanium silicalite molecular sieve, comprising: (1) Firstly mixing a silicon dioxide source, an alkali source and water to obtain a mixed solution I, wherein the alkali source is a combination of tetrapropylammonium hydroxide and alkyl glycoside; (2) Performing second mixing on the mixed solution I and water-soluble cellulose to obtain mixed solution II; (3) Thirdly, mixing the mixed solution II with a titanium source to obtain a mixed solution III; (4) Crystallizing the mixed solution III, and roasting the obtained solid product to obtain a titanium-silicon molecular sieve; The molar ratio of the silicon dioxide source to the alkali source to the water-soluble cellulose to the titanium source to the water is 1:0.1-0.5:0.0001-0.005:0.01-0.2:20-100.
  2. 2. The method of claim 1, wherein in step (1), the tetrapropylammonium hydroxide and the alkyl glycoside are used in a molar ratio of 1:0.01-0.05.
  3. 3. The method according to claim 2, wherein in step (1), the alkyl glycoside is selected from at least one of n-octyl glucoside, decyl glucoside, lauryl glucoside, tetradecyl glucoside, hexadecyl glucoside.
  4. 4. A method according to any one of claims 1 to 3, wherein in step (1) the silica source is hydrophilic white carbon black and/or hydrophilic nanosilica; And/or the purity of the silicon dioxide source is more than or equal to 99 percent, and the particle size is less than or equal to 40nm.
  5. 5. A method according to any one of claims 1 to 3, wherein in step (2), the water-soluble cellulose is selected from at least one of hydroxymethyl cellulose, hydroxyethyl cellulose, hydroxypropyl cellulose, hydroxyethyl methyl cellulose, hydroxypropyl methyl cellulose; And/or, in step (3), the titanium source is tetrabutyl titanate and/or tetrapropyl titanate.
  6. 6. The method according to any one of claims 1 to 3, wherein in the step (4), the crystallization conditions include a temperature of 150 to 200 ℃ for 30 to 192 hours; and/or the roasting condition comprises that the temperature is 500-650 ℃ and the time is 4-20h.
  7. 7. A titanium silicalite molecular sieve prepared by the process of any one of claims 1-6.
  8. 8. The use of the titanium silicalite molecular sieve of claim 7 in catalyzing the oxidation of ethylene sulfite.
  9. 9. The method for preparing the vinyl sulfate is characterized by comprising the steps of carrying out oxidation reaction on the vinyl sulfite and hydrogen peroxide in the presence of a catalyst to obtain the vinyl sulfate; The catalyst is the titanium silicalite molecular sieve of claim 7.
  10. 10. The method according to claim 9, wherein the molar ratio of the ethylene sulfite to the hydrogen peroxide is 1:1.2-1.4; And/or the oxidation reaction conditions comprise a temperature of 20-70 ℃, a pressure of 0.1-1.0Mpa and a liquid hourly space velocity of 0.1-20h -1 .

Description

Titanium silicon molecular sieve, preparation method thereof and application thereof in catalyzing ethylene sulfite oxidation reaction Technical Field The invention relates to the field of molecular sieve synthesis, in particular to a titanium silicon molecular sieve, a preparation method thereof and application thereof in catalyzing ethylene sulfite oxidation reaction. Background The titanium-silicon molecular sieve has an MFI type topological structure which is the same as ZSM-5, and has special catalytic activity after isomorphous substitution of titanium atoms and silicon atoms, so that the titanium-silicon molecular sieve has wide application in olefin epoxidation reaction, aromatic hydrocarbon hydroxylation, ethylene sulfite oxidation and other reactions. Researchers have been searching for a cheap and stable synthesis method of titanium-silicon molecular sieves for many years due to the fact that the synthesis difficulty of the isomorphous substitution of titanium atoms is high and the influence factors are many. In the prior art, a hydrothermal synthesis method is generally adopted for the synthesis of the titanium-silicon molecular sieve, an organic silicon source and an organic titanium source are mostly adopted in the synthesis process, and secondary crystallization is often required for further supplementing the titanium source to enhance the catalytic activity of the titanium-silicon molecular sieve when an inorganic silicon source is adopted for the synthesis. CN102627293a discloses a method for synthesizing titanium-silicon molecular sieve, which adopts tetraethyl silicate and tetrabutyl titanate as silicon source and titanium source, and can prepare titanium-silicon molecular sieve after the processes of mixing raw materials, hydrolysis, alcohol expelling, hydrothermal crystallization and the like. The organic silicon source is adopted in the synthesis process, so that ethanol generated by hydrolysis of the organic silicon source is volatilized and removed through an alcohol expelling process during synthesis, the condition that the ethanol does not influence the subsequent synthesis process is ensured, the whole process consumes longer time, and the alcohol expelling process is not easy to control. CN103214001a discloses a preparation method of high-performance titanium silicalite molecular sieve, the preparation process needs to prepare micron-sized titanium silicalite molecular sieve by hydrothermal method, and finally prepares high-performance titanium silicalite molecular sieve by alkaline washing, replenishing titanium source, crystallizing and other processes. The synthetic process needs multiple crystallization, the operation is complex, and the energy consumption is high. Disclosure of Invention The invention aims to provide a titanium silicalite molecular sieve with high conversion rate of ethylene sulfite and high selectivity of ethylene sulfate. To achieve the above object, a first aspect of the present invention provides a method for preparing a titanium silicalite molecular sieve, the method comprising: (1) Firstly mixing a silicon dioxide source, an alkali source and water to obtain a mixed solution I, wherein the alkali source is a combination of tetrapropylammonium hydroxide and alkyl glycoside; (2) Performing second mixing on the mixed solution I and water-soluble cellulose to obtain mixed solution II; (3) Thirdly, mixing the mixed solution II with a titanium source to obtain a mixed solution III; (4) Crystallizing the mixed solution III, and roasting the obtained solid product to obtain a titanium-silicon molecular sieve; The molar ratio of the silicon dioxide source to the alkali source to the water-soluble cellulose to the titanium source to the water is 1:0.1-0.5:0.0001-0.005:0.01-0.2:20-100. In a second aspect the present invention provides a titanium silicalite molecular sieve prepared by the process of the first aspect. In a third aspect, the invention provides the use of the titanium silicalite molecular sieve of the second aspect in the catalysis of ethylene sulfite oxidation. The fourth aspect of the invention provides a method for preparing vinyl sulfate, comprising the steps of carrying out oxidation reaction on vinyl sulfite and hydrogen peroxide in the presence of a catalyst to obtain vinyl sulfate; The catalyst is the titanium silicalite molecular sieve of the second aspect. The method provided by the invention has the advantages that the process is simple, the repeatability is good, the alcohol expelling process and the secondary crystallization process in the traditional titanium-silicon molecular sieve synthesis process can be omitted, meanwhile, the cost can be greatly reduced by adopting a silicon dioxide source, and the titanium-silicon molecular sieve prepared by the method provided by the invention has high ethylene sulfite conversion rate and high ethylene sulfate selectivity. Drawings FIG. 1 is an XRD spectrum of a titanium silicalite molecular siev